Reversible drive for revolutions



Feb. 2T, 1950 s. A. E. LUNDIN REVERSIBLE DRIVE FOR REVOLUTIONS COUNTER 4 Sheets-Sheet 1 Filed July 8, 1947 lil A-rrmmu S. A. E. LUNDIN REVERSIBLE DRIVE FOR REVOLUTIONS COUNTER Feb. 21, 1950 4 Sheets-Sheet 2 Filed July 8, .1947

Arrow":

Feb. 21, 1950 LUNDIN 2,498,130

REVERSIBLE DRIVE FOR REVOLUTIONS COUNTER Filed July 8, 1947 4 Sheets-Sheet 3 FIE. 9

Inventor SVEN AXEL EVERT LUNDIN. 87

Arronuavs Feb. 21, 1950 s. A. E. LUNDIN 2,493,130

REVERSIBLE DRIVE FOR REVOLUTIONS COUNTER Filed July 8, 1947 4 Sheets-Sheet 4 Inventor SVEN AXEL EVERT IUNOIN ATTORNEYS Patented Feb. 21 1956 REVERSIBLE DRIVE FOR REVOLUTIONS COUNTER Sven Axel Evert Lundin, Malmo, Sweden, assignor to Aktiebolaget Addo, Malmo, Sweden, a corporation of Sweden Application July 8, 1947, Serial No. 759,678 In Sweden July 29, 1946 Claims.

The present invention relates to a driving mechanism for revolutions counting or multiplier registers with tens transmission in calculating machines of the Odhner type. In such machines the revolutions counting register shall show 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 etc. irrespectively ofwhether the initial rotation movement of the crank shaft takes place in the clockwise or the counter-clockwise direction.

An object of the invention is to provide such a, driving mechanism requiring very small space in the machine, especially in its lateral direction.

Another object of the invention is to provide such a driving mechanism which may be constructed so as to be supplied as a special mounting set which, at low cost, may be inserted in a standard machine having no such mechanism without having to exchange the frame and housing of the machine. Previously known mechanisms of the type in question require however such a great space, especially in the lateral direction of the machine, that insertion in a standard machine which from the beginning has no such mechanism can hardly be contemplated.

A further object of the invention is to provide a driving mechanism of the type in question which is operable by means of the driving handle of the machine for driving the revolutions counting register toward higher numbers with an optional direction of rotation of the handle.

Still another object of the invention is to provide adriving mechanism of the type in question which is optionally adjustable in either of two operative positions for driving the revolutions counting register towards higher numbers upon rotation of the handle in either direction and in an inoperative position in which it is automatically restored upon zero setting of the revolutions counting register.

A further object of the invention is to provide a driving mechanism of the type in question in result and revolutions counting registers.

Fig. 2 is a side view of the machine from the left in Fig. 1.

Fig. 3 shows a locking means for the handle of the machine.

Fig. 4 is a section from the left in Fig. 1, taken just inside the left end of the machine and shows a driving mechanism according to the invention.

Fig. 5 is a section from the right in Fig. 1, taken somewhat further to the left in the machine than the section according to Fig. 4 (this section is also indicated with the line V-V in Fig. 16) and shows the driving mechanism according to Fig. 4 from the other side.

Fig. 6 is a view similar to Fig. 4 of certain parts of the driving mechanism in neutral position.

Fig. '7 is a view of the parts according to Fig. 6 after a certain rotation of the handle of the machine.

Fig. 8 shows the position of the gear set included in the driving mechanism according to the invention, when the driving mechanism occupies the position according to Fig. '7.

Figs. 9 and 10 correspond to Figs. 7 and 8 and show another position of the driving mechanism when the handle of the machine has effected an initial rotation movement in the direction opposite to that supposed in the case according to Figs. 7 and 8.

Fig. 11 shows a locking means for the main drive shaft upon zero setting of the revolutions counting register.

Figs. 12 and 13 show different positions during a zero setting operation of a mechanism for automatic restoring of the driving mechanism according to the invention in neutral position according to Figs. 4 to 6 upon zero setting of the revolutions counting register.

Figs. 14 and 15 similar to Fig. 5 show how the driving mechanism according to the invention is machines of the Odhner type a driving handle I is fixed on the outer end of a crank shaft 3 mounted in a sleeve 2 and carrying within the housing 4 of the machine a gear 5 meshing with a similar gear 6 on the main drive shaft 1 of the machine (see Figs. 1 and 3). On the main drive shaft there is further fixed a locking disc 8 which on a point of its periphery has a relatively broad recess 9 surrounded on two sides by locking teeth I0. When the handle I and thus the main drive shaft 1 occupy their normal position or neutral position a locking arm I2 rotatable about a fixed shaft I I on the frame of the machine projects into the recess 9 of the locking disc 8 and is held in position by a spring I3. The arrangement is such that after a certain initial rotation of the handle I and thus of the main drive shaft I, e. g., 40 in either direction the locking arm I2 engages the locking teeth II) of the disc 8 on the respective side of the recess 9 (see the position of the locking arm I2 shown with dotted lines) and prevents returning of the handle to neutral position in another way than by completion of the rotation started.

Adjacent the left end (Fig. 1) of the machine there is fixed on the main drive shaft I a mounting plate I4 (see Figs. 4 to '7, 9 and 14 to 16) on which plate two double-armed levers I5, I6 embracing the main drive shaft are mounted on a mounting pin I! each. The main drive shaft 1 extends through an aperture in a frame plate H I8 arranged adjacent the mounting plate I4 and being rotatably mounted on a shaft I9 fixed in the frame of the machine. On the shaft I9 there is adjacent one side of the frame plate I8 freely rotatably but undisplaceably mounted a gear 20 included in a gear set arranged on the frame .plate and comprising six single gears 20 to intermeshing in a single row. The gear .row is arranged in an are around the aperture in the frame plate I8, the two outer gears 2I and 25 of the row lying almost on diametrically opposite points of the aperture edge in position for engagement with a driving gear 26 arranged on the main drive shaft 1 adjacent the mounting plate I4 in one plane with the gear set 20 to 25, when the frame plate I8 is rotated about the shaft IS in the manner described in the following. The gear set 20 to 25 is held .in the adjusted position by two spring-actuated latch pawls 21 and the gear 20 engages except the adjacent gears 23 and 24 of the gear set a gear displaceably mounted on a shaft 28 in the counting register carriage 29, which latter gear, in the known manner, is adapted to drive the digit wheels SI of the revolutions counting register by means of a single tooth 32 arranged on a disc 33 fixedly connected to the gear 30. Upon displacement of the carriage 29 the gear 33 displaceable on the shaft 28 is forced to be opposite to and in engagement with the gear 20 by the fact that a fork-shaped plate 34 fixed on the stand of the machine embraces the disc 33 connected to the gear '33 by means of its fork arms.

On the frame plate I8 there is pivotally mounted a double-armed latch pawl '35 one arm of which is actuated by a draw spring 35 tending to press a lug 31 arranged on the other arm of the latch pawl and projecting toward the other side of the .frame plate I8 through a slot connected to the aperture provided in the frame .plate for the main drive shaft I, against a looking bar 38 fixed on the machine frame. In'the mid position or neutral position of the frame plate I8 the spring .36 holds the latch pawl 35 with its lug 31 in contact with a central projection 39 of the locking bar 38, which projection is limited by steep side walls. In this position the lug 31 of the latch pawl 35 is partly situated in the space between the one ends of the levers l5 and I6 mounted on themounting plate I4 of the main drive shaft "I, so that either of the levers I5 and I6 upon rotation of the main drive shaft in either direction will meet the lug 31 and thereby swing the frame plate I8 about the shaft I9 until the lug 31 of the latch pawl 35 under the action of the spring 36 falls down from the central projection 39 of the locking bar 38, the lug 3'! being moved out of the path of the levers I5 and I6, so that the main drive shaft I may be freely rotated in the desired direction without actuation of the frame plate I8 thus adjusted. The angle of rotation of the main drive shaft I necessary for moving the lug 31 out of the way is smaller than the angle necessary for the locking arm 12 (see Fig. 3) to engage the locking teeth I0, so that after the initial rotation of the main drive shaft I for moving the latch pawl lug 31 out of the way it is possible to rotate the main drive shaft in any direction without having to complete the revolution initially started. The one arm ends of the levers I5 and I6 are held in the proper position for engagement with the latch pawl lug 37 by means of a spring 41! pressing the other arm ends of the levers against the main drive shaft I.

In the mid position or neutral position'the frame plate I8 is held by two locking levers M and 42, the locking lever II having at its one end a W-shaped edge which by means of a draw spring 43 actuating the lever 4| is pressed against a pin 14 on the frame plate I8, while the locking lever 42 at its one end has an M-shaped edge which is pressed against a pin on the frame plate I8 by means of a draw spring ifi actuating the lever 32. In the neutral position the pins 44 and 45 of the frame plate I8 rest in the central depressions of the W- and M-shaped edges of the locking levers (see Figs. 5 and 6).

When the handle I is initially rotated in sub tractive direction, i. e. when the main drive shaft I is rotated in the counter-clockwise direction with respect to Figs. '7 and 8, the end .of the lever I5 mounted on the mounting plate of the main drive shaft I meets the lug 31 of the latch pawl 35 and moves said lug together with the frame plate I8 until the lug 31 leaves the lower edge of the projection 39 as shown in Fig. 7,. Upon this tilting of the frame plate I8 the pins 44 and 45 slide out of the central depressions in the W- and M-shaped edge portions of the locking levers fiI and 42 pressing the levers out of the way against the action of their draw springs 43 and 45. After the tilting described of the frame plate I8 the parts occupy the positions shown in Fig. 7 and 8. Thus the outer gear 25 of the gear set 25 to 2.5 has been brought into engagement with the driving gear on the main drive shaft 1, so that the motion of the driving gear is transmitted to the gear 20 driving the revolutions counting register of the machine through the gear 30 and the driving tooth 32. If the main drive shaft 1 is caused to complete the started revolution in the counter-clockwise direction the gear 20 is rotated onerevolution in the clockwise direction, :the digit wheel situated at the moment opposite the driving i-tooth 3.2 being advanced in the known manner one step to the next higher digit .by means of said driving tooth 32. If, however, after the small initial movement for tilting of the frame plate I .8 to the position shown in Figs. 7 and 8 the main drive shaft I is returned and caused to effect arevolution in the clockwise direction or if after .a rotation of one or more revolutions in the counterclockwise direction the .shaft I iscaused to ro- "15 tate in the clockwise direction the above described movement in reversed,so that the digit This adjusted position of the frame plate I8.

is made visible to the operator by means of an indicator having the form of a sector 48 rotatable about a pivot 41 fixed on the machine frame, said sector having a recess 49 in which a pin 50 on the frame plate I8 is engaged. The bent peripheral edge of the sector 48 is provided at its lower end with e. g. a minus sign which, in the position according to Fig. 7 is visible through a window 5| in the machine housing 4. -In the neutral position of the frame plate |8 according to Fig. 6 the central portion of the bent edge of the sector 48 is situated before the window 5|, this portion being provided with e. g. a zero in order to indicate that the frame plate l8 occupies neutral position.

When the initial rotation of the main drive shaft 1 is effected in the clockwise direction with respect to Figs. 9 and 10, i. e. when the handle I is rotated in additive direction the lug 31 of the latch pawl 35 is moved away from the projection 39 of the locking bar 38 over the upper edge of the lever l6 arranged on the mounting plate |4, so that the frame plate 18 is swung in the clockwise direction to the operative position shown in Figs-9 and 10, while the pins 44 and 45 are moved away from the central depressions of the W- and M-shaped edge portions of the locking levers 4| and 42. When the frame plate I8 is swung in such a way the outer gear 2| of the gear set 20 to 25 is brought into engagement with the driving gear 26 fixed on the main drive shaft 1, so that upon continued rotation of the main drive shaft in the clockwise direction the gear 20 is rotated in the clockwise direction. Thus, through the gear 30 and the driving tooth 32, the gear 20 will drive the digit wheel 3| of the revolutions counting register of the machine aligned with the driving tooth 32 one step to the next higher digit upon each full revolution of the handle I in additive direction. If, after the small rotation which is necessary for swinging the frame plate [8 to the position according to Figs. 9 and 10, the handle is returned and caused to effect one or more revolutions in subtractive direction or if after one or more revolutions in additive direction the handle is caused to make one or more revolutions in subtractive direction the gear 20, as will readily be seen, will rotate the digit wheel 3| in question one step to the next lower digit for each revolution of the handle in subtractivedirection. The operative position of the frame plate I8 shown in Figs. 9 and may therefore be called'the additive adjustment position which is made visible to the operator in that the upper edge portion of the indicating sector, which portion may be marked e. g. with a plus sign is swung to g a position opposite the window 5| in the machine housing 4.

f ,In the embodiment shown the frame plate It! is adapted to be returned fully automatically fr'omitsoperative positions to the neutral midposition upon zero setting of the revolutions counting'register of the machine. Zero setting of the revolutions counting register is effected in the'known manner by rotating a shaft 52 carrying the digit wheels 3| through one revolution by means of a handle 53. The zero setting may of course be effected only when the handle I oocupies neutral position. For that reason there are mounted two curved discs 54, 55 (Fig. 11) on the shaft 52, one 54 of which discs has a recess whereas the other 55 has a projection for cooperation with two pins or rollers 56 on two arms or a coupling lever 58 mounted on a shart 51, in

such a way that the arm of the coupling lever,

which extends to the right in Fig. 11 and the end of which is fork-shaped, immediately at the beginmng of the rotation of the shaft 52 is forced downwardly and immediately at the end of the zero setting revolution of the shaft 52 is forced back to the normal position shown. The forkshaped arm of the coupling lever 58 embraces a lug 59 on one arm of a latch pawl 6i rotatable about a pivot 60, the other arm of which is provided with a nose 62 for engagement with an edge recess 63 in a circular disc 54 non-rotatably fixed on the main drive shaft .1. The guided downward swinging of the fork-shaped arm of the coupling lever 58 at the beginning of the zero setting revolution of the shaft 52 may thus take place only when the edge recess of the disc 64 fixed on the main drive shaft 1 is situated opposite the nose 62 of the latch pawl 6i which is the case when the main drive shaft 1 and thus the handle i occupies normal position as otherwise the nose 82 of the latch pawl 6| meets the periphery of the disc 54 and prevents the swinging of the coupling lever 58 and thereby rotation of the shaft 52.

On the shaft 52 there is further fixed a cam plate 65 (see Figs. 12 and 13) against which a roller 66 on one arm of a lever 68 rotatable about a pivot 61 on the counting register carriage is applied. The other arm of the lever 68 is applied against the underside of a pivot 69 on one of two plates 10 mounted on a shaft 1| on the counting register carriage and carrying between each other a bar 12 the length of which corresponds to the length of the lateral displacement of the revolutions counting register. The bar 12 is applied against the end of a link 14 mounted on the machine frame by means of pins 13 pro vided with rollers (see also Figs. 5, l4 and 15), which link is pressed against the bar 12 by a draw spring 15, which bar 12 under the intermediary of the plate 10, the pin 69 and the lever 68 rests against the cam plate 55.

When the zero setting shaft 52 is rotated in the clockwise direction with respect to Figs. 12 and 13 the cam plate 65 rotates the lever 68 in the counter-clockwise direction from the position shown in Fig. 12 to the position shown in Fig. 13, the bar 12 displacing the link 14 to the right with respect to Figs. 12 and 14 against the action of the spring 15. Immediately at the beginning of this displacement of the link 14 a cam surface 16 arranged on the link 14 swings a lever 19 mounted on a fixed pivot 18 on the machine frame and applied against the said cam surface with a roller 'l'l in the counter-clockwise direction, see Fig. 14 which shows an intermediate position during the displacement of the link 14 to the right. The upper arm of the lever 19 is applied against a roller on the downwardly extending arm of the locking lever 42, so that the M-shaped edge portion of the lever 42 at the beginning of the displacement of the link 74 is lifted out of the path of the pin 45 of the frame plate l8 (see Fig. 14). The link 14' carries also a roller 8| engaging an angle-shaped slot 82 in a lever84- In: theznormal .position of'ithea link. I 4: (Fig. .5) ithey.

roller. 81: isi-situatediin the lower: branch-.oirthe; anglee-shaped: slot. 82-..in the-.-.lever 84rthe. upper,- arm of which in this.position.lieseoblicmely above. and at a distance from .the lugs at. of. thelockinm 16V1Y 35 Immediately atathe beginning .of. the

displacementmf thezlink 14 to .theg-right. theroller. slidesiup into. theaupper; branch; of.. the slot... fll-swinginggthe lever- 84min). suchi-a.wayrthat. the upper arm of; the-lever; meets ;the; lug. 3.! :ot the latch pawl 35, situated. beside..thetprojection..39.. of the locking 1bar.- S8...and .moves. said.- lug out; of theapathof the proiectionri 9-in;.,r.elati0n;.to ,the,' has The frame; plate; 18. occupying. additive. (Big,- .9). or subtractiveefiFigs. .Land. 14); Working; position: isihereafter; heldiin. working positionby. the. locking lever-114;! only. butlmay relatively easily be;- moved=.to; neutral.-.position, againstthe action, of. the. draw; spring; 43- of the; lockin ilever. Lil owingto. the; W.-shaped .form .of, ther-lockingnor tion .of thelever. This restorationjsieffeete d. by,

the fact that..a; .r.o11.er 8,5, mountedgonv the; frame, plate 1.8. at the.-end..of;. the; displacement. oi.. th.e.. link...'|4..to. the right: with respectte Eigs, 1 4 and 15; meetseither of twoccamsurfaces 85, and 8,3

of. the linhjiwhich are. arran ediinxviorm in relation-.to.:.each other-and- WhichatthfiyiiSQldCQT mentofthelink. forcetheziramepl te. l .83 0. win

to..-neutral position, the pinfidofthe frame plate snappingintothe centraLdepression of the w haped locking; portion oithe. locki i vc ii so. that; theframe. p1ate.;is.:.-he1d.-. in;. eutra posi i n. until it is further locked in this position hy. the, lo kin lever 41in; the-mann r; describ din, the following. The cam surface 86., actuates the roller-$5, ofthe frame plate l8 when said plate i to. be res ored. fr m; ub r ctive p s tion, a cording to Figs. Tend- 14., whilethelcam surface, 81: swingstheframe. platewhen, the-latter occupies. additive; working: position. according,- to Fig;..9,

- During-the last smallparpt. of therotationpf the zero; setting shaft. 52 the roller- 66;. of: the lever 68. (Fig. 13) isrolling downa; steep inclinedjportion. of 1 the cam 6 5ybac-k ,to; its .normalposition, the link. '14. beingthus rapidly moved. back. to the normal, position under; the action ofthe draw spring '15.

Hereby the-pivot ti, oftheiinlcretumsthelever.

8.4, to thenormal position,.the.lug; 3,1. of the latch pawl being moved-irigcontact with the projec-- tion 39 of the locking par 3.8;by the draw spring 36 of thalat-ch. pawl, while ther camsurface '16 of 1 the linklets the lever. 1B. r,eturn to, the: normal positionundenaction;0i thedraw spring tafi of the locking lever 3,2-, the M -shaped.locking-. portion of the locking ,;l ever.,seizing. with its projections the. pin of the frame plate L8 and holding the frame plate in neutral position (see Fig.5).

Of course the inventionmustnot be considered, as limitedto the embodiment describedaboveand shown in the drawingsfor, important modificae tions may bemade without, departing fromthe. inventive, idea aswill readily; be seen by those skilled in theart. f Asregard'sthe gear,- set 20 to 25. it may especiallybe observedlthat the numberof' the gears. may, be. another. than; the number. shown, provided thatthe. gear setfulfillsthe con-.1 ditions indicatedin the claims. Likewise thecoupling of the driving gear; 25,,with, the gearsetmay. be. effected. in, another waythan by. swinging. a. frame plate 18, for the gear set. The coupling of. the gear set. with the: driving gearneed not be, made automatically by means of an initial; move+ ment .ofx'rotation. of; the main drive; shaft of. the.

amazed:

machinealthou h hats msa sbeim stsuitsb e The .-.resto.. al Q 1: he ear: et, in neutral. p.osi ti nizmay so e ma am; another. man r: he automatically upon zero; setting; f; he; '.ev iu..-.-.

. tions.countingregister What, I- claim and; desire to secure; by Letters; Patent is:

1. In calculatingmachines of having a main drive shaftand a1 revolutions counting or multiplier register; with tens. trans..

'mission means; a driving mechanismdncluding as.

driving gear, onisaid main drivegshaft, i..1S e,t'i Off; ears intermeshingvso; as to.-. constitute; an; open; transmission'gear chain,- mounting means for. said; gear set; means, for supporting said: mounting; meansswingablein either directionarounda filly. crum coaxial with the axis ofg'one .0 f th;gal,$fli; said'gear set, meansacontrolled hy saidgmaindriveg shaft for swinging said mounting means in either; direction, depending on thedirectionoi;the initiali rotatory movement or said maindrive shaft when; starting a calculating; operation, for connecting one end and the other; respectively; ,of: saiddransa. mission gear chainwith saidldrivinggear saidg transmission gear chain altering the direction of,

the torque exerted by saiddriving gear an even number of times-from one end of. the chain to. the; other when counting fromsaiddriving gear, and; means for driving said multiplier register from;

. that gear of said gear. set, being coaxialzwith said-i fulcrum.

2. In calculating machines of-theOdhnep type; having. a main driveshaftanda revolutions count ingor multiplier register with tens transmission. means and zero setting means a driving; Inechae nismincluding'a drivin gear on saidmaindrive; shaft, a setvof gears'intermeshingso.as-,to;consti tute arr open transmissiongear chain, mounting; means for said gear set, means for supporting said, mounting means swingable in either direction; around'a fulcrumhoaxial with the' axisoi one-of, the; gears of said gear set means, controlled-by said main drive shaft for-swinging. said'mounting means in either direction; depending on the direcation of. the initial rotatorymovement of said,.,ma .i

drive, shaft when starting. a; calculating; opera:- tion, for connecting; one end-and the 1013 1 1; r e spectively, of said transmission geap-chainwith said driving; gear, said transmission gear, chain. alteringthe direction of the torque; exerted by; said driving gear; aneven number. of. times from. one end of the chain to-theother when; counting from said driving gear means; for positioning of said transmission gear chain whollyoutof mesh with said, driving; gear upon actuation, ofsaid zero setting, means, andmeansfor driving; said: multiplier. register from. one of the gears. ofsaid; gearset;

3. In calculating machines of the Odhner type; having'a main. drive shaft and a revolutions counting or multiplier register with-tens-transa mission. means and zero setting; means, a driv ingmechanism including. a driving gear; on said; main drive shaft,an even number of single gears intermeshing; in a single row, amounting plate.

for, said gearsin said gear row, means forsupe. porting said mountingplateswingable. in either; direction around a fulcrum coaxial with theaxis of one of thejgears insaid gear row, m eans.. controlled by said main drive-shaft.forswingingsaid; mounting plate; in either direction, depending on the direction of the; initial rotatory movement;- of said. main drive. Shaft; when starting amalg ula ine peration; for: conne in one-rend. ears and the. other, respective1y-, ,of said eazxrow withi said driving gear, means for positioning said gear row wholly out of mesh with said driving gear upon actuation of said zero setting means, indicating means visually indicating for the operator the momentary position of said mounting plate, and means for driving said multiplier register from one of the gears in said gear row.

4. In calculating machines of the Odhner type having a main drive shaft and a revolutions counting or multiplier register with tens transmission means and zero setting means, a driving mechanism including a driving gear on said main drive shaft, a set of gears intermeshing so as to constitute an open transmission gear chain, means for establishing connection between one end of said transmission gear chain and said driving gear when during a calculating operation the initial rotatory movement of said main drive shaft is accomplished in one direction, and for establishing connection between v the other end of said transmission gear chain and said driving gear when during a calculating operation the initial rotatory movement of said main drive shaft is accomplished in the other direction, said transmission gear chain altering the direction of the torque exerted by said driving gear an even number of times from the one end of the chain to the other when counting from said driving gear, locking means for automatically maintaining said connection between either end of said transmission gear chain and said driving gear irrespective of the direction of the rotatory movement of said main drive shaft following said initial rotatory movement thereof, means for driving said multiplier register from one of the gears in said gear train, and means for releasing said locking means and positioning of said transmission gear chain wholly out of mesh with said driving gear upon actuation of said zero setting means.

5. In calculating machines of the Odhner type having a main drive shaft and a revolutions counting or multiplier register with tens transmission means and zero setting means, a driving mechanism including a driving gear on said main drive shaft, a set of gears intermeshing so as to constitute an open transmission gear chain, mounting means for said gear set, means for supporting said mounting means swingable in either direction around a fulcrum coaxial with the aXis of one of the gears of said gear set, means controlled by said main drive shaft for swinging said mounting means in either direction, depending on the direction of the initial rotatory movement of said main drive shaft when starting a calculating operation, for establishing connection between one end and the other, respectively, of said transmission gear chain with said driving gear, said transmission gear chain altering the direction of the torque exerted by said driving gear an even number of times from one end of the chain to the other when counting from said driving gear, locking means for automatically maintaining said connection between either end of said transmission gear chain and said driving gear irrespective of the direction of the rotatory movement of said main drive shaft following said initial rotatory movement thereof, means for releasing said locking means and positioning of said transmission gear chain wholly out of mesh with said driving gear upon actuation of said zero setting means, and means for driving said multiplier register from one of the gears of said gear set.

SVEN AXEL EVERT LUNDIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,173,062 Trinks Feb. 22, 1916 1,400,004 Schaller Dec. 13, 1921 1,949,740 Friden Mar. 6, 1934 2,260,291 Britten, Jr Oct. 28, 1941 2,393,019 Avery Jan. 15, 1946 

